'Attack' on EU
Semashko said on Wednesday that Minsk had transferred $187m "to settle our debt to Gazprom" and had demanded that "Gazprom pay Beltransgaz $260m by 10:00 am (0700 GMT) tomorrow".
"If this is not done, we will be forced to shut down hydrocarbon transit through Belarussian territory," he said.
Guenther Oettinger, the EU energy commissioner, has described the disagreement between the ex-Soviet neighbours as an "attack" on the whole European Union.
He said Lithuania, which gets all of its Russian gas via Belarus, reported a 40 per cent drop in supplies on Wednesday.
Russia had earlier cut gas supplies to Belarus by nearly two-thirds on Wednesday, as the payment dispute claimed its first European victim when Lithuania said it had suffered a 40 per cent reduction in supplies pumped through Belarus.
"This isn't only a problem for this one member state, it is a problem, it is an attack on the whole European Union," Oettinger said in Brussels, the Belgian capital.
The EU commissioner urged Moscow and Minsk to honour their commitments to Europe, stressing that "their problems should not be our problems".
In a dramatic television appearance for the third day running, the chief executive of Gazprom said the company was cutting Belarus' supplies by 60 per cent from Wednesday morning but said European customers should not worry.
"Transit of Russian gas through the territory of Belarus is being implemented in the full amount and consumers of Russian gas do not experience any problems with it," Alexei Miller said in comments released by his company.
"The bad news is the Belarussian side is undertaking no action to settle the debt for Russian gas supplies," he said.
Miller said the cuts would continue in proportion to Belarus's outstanding debt.
The dispute centres on Belarus' refusal to accept a jump in the price it pays for Russian gas from the $150 per 1,000 cubic metres it paid on average last year, to $169.20 in the first quarter of this year and $184.80 in the second quarter.
Gazprom has said it would incrementally reduce gas supplies up to 85 per cent of the normal volume if the debt is not settled in the coming days.
Following Tuesday's cut, Alexander Lukashenko, the Belarusian president, ordered a shutdown of Russian gas transit deliveries to Europe in retaliation.
The move raised fears in the EU, whose members Lithuania, Germany and Poland depend on Russian gas piped through Belarus.
Analysts say the dispute has been sharpened by Lukashenko turning away from the country's traditional reliance on the Kremlin and pursuing closer ties with the EU.